Alkali-activated slag is a widely used low-carbon binder. Incorporation of textile can mitigate the brittle weakness of alkali-activated composites. The bonding between fibers and matrix is critical for the performance of textile reinforced mortar. This paper is focused on the effect of different treatment methods on the bonding properties of carbon fiber in alkali-activated slag. The interfacial shear strength of fiber bundles in matrix was determined by the pull-out test. The flexural strength of the reinforced mortar was evaluated by a repeated bending. A scanning electron microscopy test was performed to characterize the interfacial properties of the fiber bundles. The results show that the interfacial shear strength of carbon fibers in matrix is improved by the electroplating with calcium silica slurry (CSS), impregnation in different solutions, and plasma treatments. An electroplating in CSS has the best improvement in the bonding strength with an increase by 620%. The CSS treatment increases the maximum flexural strength of CFT reinforced mortar with 22.5% and 30% at 7 and 28 d respectively, and it significantly inhibits the crack growth under the cyclic loading. This effect becomes more significant after a longer curing age. The electroplating treatment eliminates the cracks in the interface of fiber yarns. Slag reacts with the plated portlandite to strengthen the bonding between mortar and fiber bundles, so it has a better inhibiting effect on the crack growth after a longer curing. © 2023 The Authors

A systematic investigation of phosphorus-based flame-retardant (PFR) systems in acrylonitrile-butadiene-styrene (ABS) is presented. The effect of various PFRs, combinations thereof and influence of different synergists is studied in terms of fire and mechanical performance, as well as toxicity of resulting ABS. Sustainable flame-retardant systems with a promising effect on the fire-retardant properties of ABS are identified: A combination of aluminum diethylphosphinate and ammonium polyphosphate is shown to exhibit superior flame-retardant properties in ABS compared to other studied PFRs and PFR combinations. Among a variety of studied potential synergists for this system, a grade of expandable graphite with a high-initiation temperature and a molybdenum-based smoke suppressant show the most promising effect, leading to a significant reduction of the peak heat release rate as well as the smoke production rate. Compared to current state-of-the-art brominated flame-retardant for ABS, the identified flame-retardant systems reduce the maximum smoke production rate by 70% and the peak heat release rate by 40%. However, a significant reduction of the impact performance of the resulting ABS is identified, which requires further investigation.

The present report addresses the Deliverables 2.1 and 2.2 of the project ‘Green cement based on blast-furnace slag’. Deliverable 2.1 aims at the evaluation of the mechanical and thermal performance of commercial reinforcements. Deliverable 2.2 describes the modification of those commercial reinforcements and evaluation.Two different commercial textile reinforcement grids for concrete were evaluated: (i) a basalt-fibre grid from US Basalt impregnated with epoxy resin and (ii) a carbon fibre grid from V. Fraas that is impregnated with Styrene-butadiene rubber (SBR). The grids were exposed to plasma oxidation to increase their hydrophilicity and create functional groups that can react with the uncured cement. The adhesion to the green cement matrix was then measured of both, the untreated and the plasma treated grids by pull-out testing of fibre bundles.

The present report addresses the Deliverable 2.3 of the project ‘Green cement based on blast-furnace slag’. Deliverable 2.3 aims at the development of new textile reinforcements with improved adhesion and thermal stability for green cements.Two different approaches for impregnation of textile reinforcements with materials that exhibit good adhesion to cementitious matrices as well as good thermal stability were studied: (i) impregnation with cementitious materials, (ii) impregnation with molecular precursors. Moreover, a nano-CSH impregnation system developed at Chalmers was characterized and compared to the systems developed at RISE.

Halogen-free flame-retardants (HFFRs) have a pronounced effect on the impact performance of ABS. The addition of flame-retardant (FR) particles may interfere with the morphology of ABS or introduce weak spots into the plastic. The present work studies the morphology of ABS with phosphorus-based flame-retardant systems and sets it in relation to their respective impact performance with the aim of identifying mechanisms influencing the impact performance and revealing possibilities to overcome this issue.

Electrocoating at constant current is less sensitive to moisture and oxygen than electrocoating at controlled potential, which makes it more interesting for industrial implementation. The galvanostatic electrocoating of carbon fibres with Poly(methylmethacrylate) (PMMA) was therefore studied and compared to the well researched potentiostatic electrocoating procedure. The influence of different experimental parameters on the coating efficiency was investigated in order to identify the mechanisms that are involved in the cathodic electrocoating at constant current. It could be confirmed that the involved mechanisms differ from potentiostatic electrocoating and it was found that galvanostatic electrocoating is more efficient at ambient conditions compared to potentiostatic electrocoating. Polymer layers that cover the entire carbon fibre surface could be achieved in a continuous process by galvanostatic electrocoating under ambient conditions. 

The European Green Vehicle project ENLIGHT aims to advance highly innovative lightweight material technologies for application in structural vehicle parts of future volume produced Electric Vehicles (EVs) along four axes: performance, manufacturability, cost effectiveness and lifecycle footprint. The main target is to develop viable and sustainable solutions for medium production volume up to 50.000 EVs destined to reach the market in the next 8-12 years. The specific objectives of the ENLIGHT project are on holistic and integrated conceptual design and manufacturing concerning how the technologies and materials addressed can be combined into a representative medium-volume EV. The solutions will be demonstrated in five modules: a front module and central floor module, a front door, a sub-frame and suspension system as well as a cross-car beam. In this paper, a summary of the major results obtained up to the 3rd project year will be presented. © 2016 The Authors.

In this study different concepts to attain a material that can reduce its stiffness upon external stimulation were evaluated regarding their suitability for traffic safety applications. All concepts rely on resistive heating of a carbon fibre reinforcement upon application of electric current through the fibres. The stiffness reduction is achieved by a phase transformation due to heating of the material. The phase transformation takes place either in a thermoplastic interphase, in a thermoplastic matrix or in a thermoset matrix, depending on the concept. The different concepts were studied regarding their thermomechanical and processing properties and their ability to reduce their stiffness upon application of an electric current was tested. Moreover, the materials were evaluated regarding their potential for fast activation, which is crucial for applications in traffic safety. Stiffness-reduction was achieved upon application of an electric current, where the activation temperature was between 60 and 120°C and the extent of stiffness-reduction varied between 50 and 90%, depending on the material. The response time was found to depend to a large extent on the amount of material, which leads to the conclusion that smart design solutions are required for larger parts. It is concluded that the concepts vary in their thermal, mechanical and processing properties as well as in their extent of stiffness-reduction upon activation. The results presented in this work prove the feasibility of the studied materials for traffic safety applications and the concepts allow further optimization of the materials for specific applications

Anatase nanoparticles synthesized by the sol-gel method were surface-functionalized with long alkyl chain coupling agents as compatibilizers for a nonpolar environment, containing different anchor groups for surface interaction namely phosphonate (dodecyl phosphonate), carboxylate (dodecanoic acid), sulfate (sodium dodecyl sulphate), and amine (dodecyl amine). It was shown that the surface of the nanoparticles can be functionalized with the various surface groups applying similar reaction conditions. The kind of surface interaction was analyzed applying FTIR spectroscopy. The phosphonate and the carboxylate groups interact with the surface via quite strong covalent or coordinative interactions, respectively. The sulfate and amine based coupling agents on the other hand exhibit electrostatic interactions. UV stability studies of the surface bound groups revealed different degradation mechanisms for the various functionalities and moreover showed that phosphonates are the most stable among the investigated surface capping groups.

A novel functional material allowing stiffness-reduction upon external stimulation was developed. Implementation of such technology in the design of a car front has high potential to result in increased protection of vulnerable road users (VRUs). The composite material is obtained by coating carbon fibres with a thermoplastic polymer in a continuous process, followed by infusion with an epoxy resin. The process is scalable for industrial use. The coating process was optimized regarding coating efficiency, energy consumption, risks involved for operating personnel and environment, and tailored to gain the optimal coating thickness obtained from numerical calculations. A drastic decrease in transversal stiffness could be detected for the composite material by dynamic mechanical thermal analysis (DMTA), when the temperature was increased above the glass transition temperature of the thermoplastic interphase. The ability of the material to achieve such temperature and associated reduction in stiffness by the application of current was verified using a special 3-point bending setup developed for this task.